In labeling machines, labels are applied to containers. In the process, an uncut strip of labels is unwound from a supply roller and supplied to a cutting device by means of a transport device with several rollers. In the cutting device, the strip of labels is then taken up by a vacuum roller and cut into individual labels with a cutter. The individualized labels are taken off the vacuum roller by a gripping mechanism, provided with glue at a gluing station and applied to containers.
For a precise cutting position in the cutting device, the strip of labels is usually provided with cutting marks that are embodied as highly contrasting color bars on the strip of labels. The strip of labels is passed by a position sensor in the cutting device at high speed, which sensor detects the cutting marks at a high time resolution and then emits a signal to the control unit of the cutting device. By this signal, the cutter is controlled with respect to the position of the strip of labels such that the latter is cut into individual labels at the desired cutting positions.
Moreover, a method is known from EP 2 364 918 A2 which can do without the above mentioned cutting marks. In said method, two-dimensional images of the strip of labels are taken with an image acquisition unit, and by detection of the label print, a clock signal is then generated for the cutting device.
A disadvantage in the mentioned prior art is that the well-known method is prone to errors during the learning and aligning of a strip of labels and takes a long time because an operator must manually perform a sequence of functions required for this, such as, for example, the feed motion of the strip of labels or the vacuum in the cutting device.